The invention relates to an adenovirus fiber modified by the mutation of one or more residues. The residues are directed towards the natural cell receptor in the three-dimensional structure of said adenovirus. The invention further relates to a DNA fragment, and expression vector, and a cell line expressing said fiber, and also concerns an adenovirus, the process for producing this type of adenovirus, and an infectable host cell, as well as their therapeutic application and a corresponding pharmaceutical composition.